This application is for partial funding of the International Mdm2 Workshop IV that will be held September 30-October 3, 2007 at the Marine Biologic Laboratories at Woods Hole, Massachusetts. This Workshop is held every two years, alternating between the United States and Europe, and this will be the fourth Workshop in the series. First held in 2001, this open scientific meeting brings together many investigators whose research efforts are focused on Mdm2 (or the related protein MdmX) further examine the role of these MDM proteins in regulating the p19-Mdm2-p53 signaling axis during cell proliferation and apoptosis, development, and in tumor suppression. In addition, MDM regulation of proteins other than p53 (including p73/p63) during cell growth is discussed, as are other modifiers of the p53 tumor suppressor pathway that exert their effects in conjunction with MDM proteins (for example, ATM, p3OO/CBP, HAUSP). The results of mouse modeling experiments or other in vivo data are also examined and discussed at length, and the utility of these proteins and their related modifiers as therapeutic targets for cancer treatment is fully debated. In keeping with this tradition, the International Mdm2 Workshop IV will be divided into an opening keynote session, 4 sessions of oral presentations, and two poster sessions. The session titles will be Regulation of Mdm2 and p53, Mdm2/MdmX and Other Cell Regulators of p53, Physiologic Functions of MDM Proteins, and p53 Regulators as Therapeutic Targets in Human Cancer. Although we have 2 keynote speakers and 15 invited speakers, a majority of the oral presentations (an additional 21 talks) will be scheduled from the submitted abstracts to provide ample opportunity for other speakers to present their latest findings. A broad representation of the various labs working in this field has been a particular hallmark of previous Mdm2 Workshops, and we intend to continue this tradition as well. Furthermore, we will ensure that young investigators also have the opportunity to present their data, either at poster sessions or in oral presentations during the meeting. This Workshop has previously attracted a broad audience of clinical and basic scientists working in academia or in industry, and we anticipate this trend to continue as there continues to be a great deal of interest in Mdm2 and other related p53 modifiers as targets for cancer diagnosis and therapy. [unreadable] [unreadable] [unreadable] [unreadable]